Sentiment analysis techniques can be used to assign a piece of text a single value that represents opinion expressed in that text. For example, on a scale between −1 (very negative) and +1 (very positive), the text: “Bob is a terrible trumpet player” might be assigned a score of −0.9 using sentiment analysis. As another example, the text: “Those cookies taste great!” might be assigned a score of +0.9.
One problem with existing sentiment analysis techniques is seen when the text being evaluated expresses two independent opinions, such as in the following: “Bob is a terrible trumpet player, but the cookies he bakes taste great!” Using existing techniques, the text would be assigned a neutral score—the negative and positive opinions expressed cancelling one another out. For this and other reasons, improvements in sentiment analysis techniques would be desirable.